Intro to the PNS: Spinal Cord and Spinal Nerves

Question 1

What does the PNS consist of?

Answer 1

Spinal nerves and cranial nerves

Question 2

What is the spinal cord a continuation of?

Answer 2

The medulla through the foramen magnum

Question 3

Where does the spinal cord end?

Answer 3

L1/L2 interspace

Question 4

What is the end of the spinal cord called before it becomes cauda equina?

Answer 4

Conus medullaris

Question 5

How many pair of spinal nerves are there?

Answer 5

31

Question 6

How many spinal nerves are there per section of the vertebral column?

Answer 6

8 Cervical, 12 Thoracic, 5 Lumbar, 5 Sacral, 1 Coccygeal

Question 7

What is a spinal nerve composed of?

Answer 7

Fused ventral and dorsal root

Question 8

What type of nerves are the ventral and dorsal nerves respectively?

Answer 8

Motor and sensory

Question 9

What is the nomenclature for spinal nerves from C1-C7?

Answer 9

They are named for the vertebrae below from where they come out (C1 comes out above Cv1)

Question 10

Where does C8 emerge?

Answer 10

Below C7

Question 11

What is the nomenclature for spinal nerves other than C1-C8?

Answer 11

The are named for the vertebrae above from which the emerge (L5 emerges below Lv5)

Question 12

What are the three layers of covering over the CNS from superficial to deep?

Answer 12

Dura mater, arachnoid mater, pia mater

Question 13

What is unique about the pia mater?

Answer 13

It is directly attached to the brain/spinal cord much like skin

Question 14

What connects the pia mater to the dura mater?

Answer 14

Denticulate ligaments

Question 15

What is the white matter mostly consisting of?

Answer 15

Axons and no cell bodies

Question 16

What is the grey matter mostly consisting of?

Answer 16

Cell bodies and no axons

Question 17

What is found in the dorsal portion of the spinal cord?

Answer 17

Dorsal median septum which houses the posterior spinal vein

Question 18

What is found in the ventral portion of the spinal cord?

Answer 18

Ventral median fissure with the anterior spinal artery running along the surface

Question 19

What does the dorsal root ganglion consist of and what do they do?

Answer 19

Pseudounipolar neurons getting input from sensory cells and relaying them up to the brain

Question 20

What does the ventral horn of the consist of and what do they do?

Answer 20

Alpha motor neurons that send signals to innervate muscles

Question 21

What do the ventral and dorsal root come together to form?

Answer 21

Spinal nerves

Question 22

What do spinal nerves quickly split into?

Answer 22

Dorsal and ventral ramii

Question 23

What does the dorsal ramus innervate?

Answer 23

Dorsal surface of head neck and back

Question 24

What does the ventral ramus contain?

Answer 24

Both sensory and motor neurons

Question 25

What does the ventral ramus innervate?

Answer 25

Torso and limbs

Question 26

What do ventral ramii form when they criss-cross?

Answer 26

A plexus that shares axons